Heart disease is the leading cause of death in the United States today. Cardiac motion analysis using magnetic resonance imaging has proven to be a sensitive method to detect and quantify regions of ischemia and infarction in the diseased heart. The current methodology, however, is limited by slow image acquisition times, non-automated image analysis methods, and sparse three-dimensional measurement protocols, usually limited to the left ventricle. The goals of the proposed research are to develop and validate a new, ultrafast method to image myocardial motion and strain using tagged magnetic resonance imaging and the concept of harmonic phase images. The applicants reported that harmonic phase images are instrumental in automated, accurate imaging of closely spaced tag planes, small motion fields, two-dimensional strain, and sequential two-dimensional displacement fields. Preliminary results provided in this proposal support the hypothesis that harmonic phase images can be used in real-time, two dimensional motion and strain imaging and interactive-time three-dimensional motion and strain imaging. The applicants propose to 1) characterize and optimize harmonic phase imaging methods; 2) develop, implement, and validate real-time 2-D harmonic phase imaging methods; 3) develop, implement, and validate single breath-hold 3-D harmonic phase imagine methods; and 4) develop and validate a suite of new clinical protocols using harmonic phase imaging. All methods will be extensively validated using a computer phantom, physical phantoms, and human scans. In addition, comparative studies will be conducted throughout the course of research using competing imaging, data processing, and visualization approaches. The methods to be developed for the ultrafast, automated, and accurate imaging of cardiac strain will be useful in screening for cardiac ischemic disease, rapid evaluation of myocardial infarction extent and degree, and for monitoring treatment after myocardial infarction.